On analyzing space-time distribution of evaporation duct height over the global ocean

The statistical features of the evaporation duct over the global ocean were comprehensively investigated with reanalysis data sets from the National Centers for Environmental Prediction. These data sets have time and spatial resolutions of 1 h and 0.313°x0.312°, respectively. The efficiency of the analysis was evaluated by processing weather buoy data from the Pacific Ocean and measuring propagation loss in the Yellow Sea of China. The distribution features of evaporation duct height （EDH） and the related meteorological factors for different seas were analyzed. The global EDH is generally high and demonstrates a latitudinal distribution for oceans at low latitudes. The average EDH is approximately 11 m over oceans beside the equator with a latitude of less than 20°. The reasons for the formation of the global EDH features were also analyzed for different sea areas.

小型动力堆核事故后放射性核素海洋大气扩散研究

应用于海洋的小型核反应堆技术日渐成熟,但目前核事故大气扩散研究主要针对于沿海或内陆情况。为使大气扩散计算模型适用于海洋环境,本文对高斯烟羽模型进行了修正,应用MACCS程序研究了小型动力堆严重事故所造成的后果。结果表明,若烟羽未抬升,可溶性核素积分浓度垂直分布受水体影响较大,低空的核素积分浓度明显降低;若烟羽被抬升,源项附近海面的核素积分浓度较低,水体对其产生的影响较小;整个扩散过程中,水体主要影响海面附近核素积分浓度大的区域。